Condenser



patented May i9, i925.

siren STATES PATENT OFFICE.

I coNnENsnR.

Application tiled May 23,

To all whom t may concern Be it known that I, PownL CRosLnY, Jr.,

a citizen of the United States, residing at Cincinnati. in the county of Hamilton and 5 'State of hio, have invented certain new land useful Improvements in Condensers, of

which the following is a specification.

My invention relates to improvements in electrical condensers, especially those where- J in it is desired tovary the capacity readily,

Such, for instance, as are used in radio com munication.

The object of my invention is to provide very simple construction 4for such devices, especially in the means for varying Athe ea pacity, and-yet have the device durable and accurate in its operation. A further object is to make the capacity variation more uniforminthe earlier stages of reduction from `its maximiim capacity Other objectsv will appear in the course of the ensuing de- Sciption y I- attain these objects by the device illustrated, for example, in the accompanying drawing, in whic i4- n Figure 1 is a lan view of the condenser in its closed condition of maximum capacity;

Fig. 2 is a side elevation of the same;

Fig. 3 is aA rear elevation of the same; and

Fie. 4 is a lan view, similar to Fig. 1, showing a modification.

As herein shown in Figs. 1, 2 and 3, there is a base or bracket 1 made of insulating 'material, preferably a material ermitting the. part to be molded in its required shape, such as ber or resinous composition Vmuch used for foriining insulating bodies in elec trical Work. yllhis base 1 comprises the main e body part 2 extending backward and being 40 of a length and up and down width sufiicient to afford the required area, and of a thicknessl to afford the required rigidity when made of some such material as mentioned. At its front end, this body 2 has the front leg 3 extending across therefrom at ri ht angles thereto, throughout its up and own width. The side of the body 2 remote'from the leg 3 has the recess 4 throughout its interior, leaving only a flange 5c 5,

around'the four edges, for lightness and 1921. Serial No. 471,808.

strength. A boss 6 projects back a short distance from the leg 3, midway of the height of the body 2 and leg 3, and continuous over to the 'junction of these por-v tions of the base, thereby strengthening it, and also avoiding any undercut, facilitating molding of the base. Atthe top and the bottom of the junction of these parts 2 and 3 are ears 7 and 8, respectively, projecting diagonally across tfrom the outer edge of the leg 3 to a distance well back of the rear side of the boss 6. These ears 7 and 8 also reinforce the structure of this -base l at the junction of its parts 2 and 3; and their adjacent sides are outside the upper and lower limits of the body part 2, leaving the entire side of this part next to the leg 3 unobstructed, from the boss 6 to the rear end of the part 2, which` side is flat. forming as nearly as possible a Aperfect plane surface. The front side of the leg 3 is fiat, to lie against the wall 9, which will be understood to be the front wall of a cabinet or the like, in which the condensers usually are mounted for use. u

Mounted on the lat side ot the body part 2 et this base is a thin plate or sheet of con- '.lucting material 10, preferably a very thin sheet of copper. Such material may be secured to the insulating base part 2 by any suitable means, preferably by a suitable cementing material, or a glue. This sheet 1() has an integral tongue 11- near its lower edge, projecting from its rear edge and bent around the rear end of the part 2 of the insulating base l, and a binding screw 12 passes through this tongue 11, being tapped into the insulating base 1 and serving to con-4 nect the conductor 13 to the sheet 1'() by clamping this conductor and the tongue 11 against the end of the base 1. This sheet 10 of conducting material is of substantially the full up and down width of the flat side of the base part 2, and extends substantially m the rear end thereof. .Its front edge may be 95 some distance back from the junction of the parts 2 and 3, according to circumstances .ater to be described.

The movable member 14 also is of insulat ing ntlateriah,l preferably the same kind la 10 that composing the base 1, molded into its required shape. lt is of about the same general thickness as the body of the base 1, and of the up and down width thereof, with its iront edge rounded to clear the junction of the boss 6 with the base part 2 when this member` le is` brought very close to the part 2. lts side to `lie next to the part 2 is flat, and as nearly as possible a perfect plane surface; but its opposite side preferably has a central rectangular boss 16 with ribs 17 running to the respective rear corners of the member, and ribs 18 running to hinge bosses 19 at respective front corners ot the member, from this central boss 16. Also, preferably. this boss 1b has a ceutralrectangular recess 20: the boss 16 and recess 20 being of greatest length up and down. A plate 21 of suitable wearing material, as steel, is secured in this recess 20 with its face iiush with the tace or" the boss 16.

Mounted on the tlat side. of the movable member 14 is a thin plate or sheet ot couducting material 22, preferably of the same material as thatI of the sheet 10 that is mounted on the flat surface of the base part 2, as very thin sheet copper. lt. may be secured -to the member 14 inany suitable manner, preferably the same as with the sheet 10. as with cementing material, glue or the like. This .Sheet 22 has an integral tongue 23 ucar its upper edge, projecting from its rear edge and bent around the rear end 'of the member 14, with a binding screw 24 through it and tapped into the member 14, connecting the conductor 25 to the sheet 22 by clamping` this conductor and the tongue 23 against the rear end of the member 14. This sheet 22 ot conducting material is of substantially the full width up and down as the fiat side oi' the member 14, and extends substantially to the rear end thereof. lts front edge is about coincident with that of the sheet 10 t-hat is on the base art 2 when the member 14 is assembled with the base 1; these fiat adjacent sides of the member 14 and part 2 being of substantially the same dlmensions up and down.

Hinge pms 2G pass through the ears 7 and hinge lugs or bosses 19 of the memberkd, thus connecting the member 14 to the base 1 to have its rear end about coincident with the rear, end of the base part 2 when the member is swung closest to the part 2.

Springs 2 7, each comprising a middle loop 28 around a respective projecting hinge pin 26 and member 29 projected diagonally'forwardand hookne-d into a hole 30 inthe to or bottom, as the case may be, of the liase leg 3. and a member 31 projected backward and hooked into holes .32 in edges of the member lei, act to hold the member 14 away from the part 2 of the base 1 in the absence or any1-restraining means; the normal oontessera dition of the spring 27 being one with its members 29 and 31 approached to each other. These springs 27 are held on the device by having their hook parts fitting with sufficient tightness in the holes 30 and 32; or the pins 26 may have heads 33 and fit tightly in either the ears 7 and 8 or the member 14, these heads 33 retaining the springs by engaging their loops 28; or both of these provisions may be relied upon, as indicated in the drawings.

Mounted upon one of the sheets 10 or 22 of conducting material, preferably on the conducting sheet 10 on the insulating base 1` is a very thin sheet of dielectric material 34, such as mica. This sheet 34 is of ample dimensions to completely separate the conducting sheets 10 and 22 electrically throughout their area, as required in a condenser. It is secured to the conducting sheet, as the sheet 10 as here shown, by any suitable means, preferably by a suitable cementing material, or a glue.

In the drawing, for purpose of clearness, the conducting sheets 10 and 22, and this dielectric sheet- 34, are shown as of considerable thickness; but actually, the dielectric sheet, such as mica., is extremely thin, for instance, two one-thousandths of an inch in thickness; and the 'sheets of conducting material also are preferably very thin, for instance about one, one-hundreth of an inch iu thickness. It will be understood that for maximum'capacity, the two conducting surfaces of the sheets 10 and 22 are to be as close together as possible without actually making an electrically conducting communication; and the dielectric sheet 34, while adding to the capacity by its superior dielectric properties compared with air, must be thin enough to permit the maximum-capacity closeness of the two conducting surfaces. For the same reason, the surfaces are made as nearly perfectly 'plane as is commercially practicable, so as to have this closeness yof the conducting surfaces as nearly as possible uniform throughout their area..

For this reason, I- prefer a material easily molded with very true surfaces. and not 8, respectively down into and up into the" liable to warp in use; such as the molded com ositions referred to.

e camshaft 35 extends rearwardly through a journal bearing in the leg 3 and the boss 6 thereof, preferably yhaving a bushin 36 of wearing material, as steel, aroun it in this bearing. This bushing may project somewhat rearwardly from the boss 6, adding to the rigid bearing area. for the shaft 35. The rear end of the shaft 35 is reduced, leaving a shoulder, and the cam 37 fits tightly on` this reduced part and the shaft en is riveted tightly against the cam,

This cam as here shown, is merely 'a circular disk, wat che shun as fastened in it n 'holding the cam to turn with the shaft. i

ci either example herein shown may be varied or interchanged as conditions may call for. Il`herefore while certain constructional details are deemed preferable in connection with ray-invention, and I have shown and described these rather specifically in elucidating the construction and use of my invention, as is required, I do not wish to be understood as being limited to such precise showing and description, but having thus :uli described my invention,

h at I claim as new and desire to secure byLetters Patent is:

L In a condenser, a plurality of elements having opposed dielectrically separated electrically conducting surfaces, a support on which one of said elements may be moved toward or from the other element, to vary the capacity between hsaid surfaces, manipulating means, and operating means have ing a sliding engagement with said one ci said elements to transmit movement of the manipulating means to Said one of said elements, this one of said elements yieldinglyresisting said operating means, whereby the element and the operating means have their sliding engagement throughout the movement.

2. In a condenser, a plurality of elements having opposed dielectrically separated electrically conducting surfaces, a support on which one-of said elements may be moved into or out oi substantial parallelism with the other element, to vary the capacity between said surfaces, manipulating means and operating means having a sliding engagement with said one of said elements to transmit movement of the manipulating vmeans to said one of said elements.

3. In a condenser, a plurality of elements having opposed dielectrically separated electrically conducting surfaces, a support on which one ci said elements may. be moved into or out of substantial parallelism with the other element, to vary the capacity between said suriaes, manipulating means,\and operating means having a sliding engagement with said one oi' sai-:l elements to transmit movement of the manipulating means to said one of said elements, this one of said elements yieldingly resisting said operating means, whereby the element and the operate means have their sliding 'engagement maintained throughout the movement, 1

i. In a condenser, a plurality of elements having opposed dielectrically separated elecn trically conductin surfaces, one of said ele,- ments being movable toward or away from the other element, to vary the capacity between said surfaces, manipui f'ting means, rotary operating means turned by said manipulating means, having an actuating surface eccentric to its rotation, and means holding said one of said elements toward this actuating surface, whereby said operating. means sustains maintained this element at various distances from its center ot rotation and at complementary distances from the other element, upon rotation of said operating means by said manipulating means, whereby inaccuracy of adjustment ot said manipulating means is minimized in the adjustment of this element relatively to the other element.

5. In a condenser, a plurality of elements having opp Sed dielectrically separated electrically c nductin surfaces, a support on which one of said e ements may be moved into or out or" substantial parallelism With the other element, to vary the capacity be tween said surfaces, manipulating means, rotary operating means turned by said ma nipulating means, having an actuating surface eccentric toits rotation, and means holding said one of said elements toward this actuating surface, whereby said operating means sustains this element at various distances from its center of rotation and at various angles of divergence from the other element, upon rotation of said operating'means by said manipulating means, whereby inaccuracy of adjustment of said manipulating means is minimized in adjusting the angular relation of said elements.

6. In a condenser, an electrically-insulating base comprising a body having a fiat si e and a leg projecting from one end of said body, past said dat side, a metal sheet secured to and extending across said fiat side, an electrically-insulating member having a :dat Side opposed to said flat side of said base, and being hinged to said base near the junction of said leg and said body, whereby said member may swing its fiat side substantially arallel with or divergent from said Hat si e of said base, a metal sheet secured to vand extending across said dat side o said member, a dielectric element interposed between said metal sheets, means for making electrical connections with the respective metal sheets, a cam sha-ft journaled in said leg and projecting along the other side of said member, a cam fixed on said shaft and engaging with said other side of said member, and yielding means pressin@r said member toward said cam.v

In a condenser, a plurality of elements having opposed dielectrically sepa-rated electrically conducting surfaces, a support on which one of said elements may be moved to vary the spacing between this element and the other element, to vary the capacity between said surfaces, manipulating means, androperating means transmitting the motion of the manipulating means to said one of said elements, whereby, with a constant rate of movement of said manipulating means, said oneo said elements is moved at a decreasing rate as it is v'made to approach said other element,"

8. In a condenser, a, plurality of elements having opposed dieectrieally separated elecn trioally oonductng surfaces,

va support on tween said surfaces, and operatmg means manipuatng means, transmlstmg an hm."-

momie motion to sai (me of said elements as derived from a motion 'of aanstaat rate mparted. to said manpuang means, the def crease in the harmonic motion progressing as the one element approaches the othe dement.

FVEL CRUSLY@ JR. 

